A theory of the kinetics of the absorption of calcium into bone based on a previously published theory of chromatographic kinetics has been developed by G. Weiss and collaborators. The model has been tested on a number of different normal populations, yielding results to be expected from general physiological principles. The model has been applied to patients with dermatomyositis being treated with steroids, showing that the drug-regimen impairs bone absorption to a considerable degree. Preliminary measurements have been made on different disease populations. These studies will be continued in the forthcoming year. J. Bryngelson has developed a theoretical basis for protein folding, based on statistical properties of conformational energies. The theory has been used to improve the performance of currently used protein structure prediction programs. A continuation of this project relates to the effects of water exclusion in the initial collapse phase in protein folding. It has been shown that hydrogen bonds are increasingly effective in determining secondary structure, as the protein collapses. A theory has been developed by G. Weiss to estimate the time for a gradient gel to separate peaks in electrophoresis, when diffusion effects are small but not negligible. This is combined with a concurrent measurement by M. Garner and A.Chrambach of boundary spreading as a function of the gel concentration.